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Topic Review (Newest First)

02-23-2011 10:28 AM

oldred

Quote:

Originally Posted by Derkyb

so is it best to install the refrigerated dryer upstream right after the compressor or downstream right before the outlet

Depends a lot on your line system, if the pipe from the compressor tank to the hose pressure regulator is short or for other reasons has little cooling capacity then yes just mount it close to the tank. If however the piping from the tank to the regulator is already capable of cooling the air a significant amount then a downstream location will reduce the amount of heat the unit has to remove.

02-23-2011 10:15 AM

DanielC

Old thread brought back to life.
I am going to assume this is for painting, with a HVLP gun
This is what I do. I have a small compressor, old Sears 3 HP, on a 20 gallon horizontal tank. The compressor has a regulator on it. It is in my garage. I do a lot of painting in a carport, 30 or 40 feet from the garage, or outside. But sometimes I will paint in the garage.
I also have an extra 20 gallon air tank.
When I am painting, I put the extra tank close to where I am painting. It also has a water trap on it.
I set the regulator on the air compressor to about 40 PSI, and run a hose to where ever the second tank is located. There is a water trap on the inlet of the second tank.
The air goes into the second tank, from the top, in the center. The air outlet on on one end of the second tank. I hook my spray gun up to the air outlet, and use a variable restrictor, with a pressure gauge at the gun to get the pressure I want at the gun, with the trigger pulled. I have not had a problem with water in the paint gun yet. but I live in western Oregon, so this system may be overwhelmed in Florida. Where I live, it is either cool and humid, or hot and dry. Rarely do we get high temperature, and high humidity.
My theory on what happens in my system. The air gets compressed, and heated. It loses some water in the compressor tank. Warm, humid air leaves the compressor tank, and goes through the regulator. The pressure drop there causes the air to cool some. Liquid water, and water vapor travel with the air through a host to the remote tank. The air continues to cool, and more water vapor condenses out of the air. At the second tank, the water trap catches the liquid water, and any liquid water that gets past the water trap, goes into the second tank. This air inlet is at the top of the tank, pointing down, and the water just goes to the bottom of the 20 gallon tank. The air going to the gun is pretty close to the ambient temperature, and is dry enough that it does not get below the dew point leaving the gun.

02-23-2011 09:36 AM

jaguarxk120

It would be best to have the air drier right after the compressor. That way the rest of the system will stay dry.

I worked in a manufacturing plant that had very large compressors, there were intercoolers that removed water from the compressor stages and aftercooler before the air was sent to the air driers.

You want dry air flowing to storage and into the shop system, that way water won't wash dirt/scale from lines and carry the stuff into your tools.

02-22-2011 10:28 PM

Derkyb

so is it best to install the refrigerated dryer upstream right after the compressor or downstream right before the outlet

04-20-2009 03:31 PM

930dreamer

Having added 30 ft of air hose before the moisture trap made a huge difference in my shop. The dissicant will work great just allow the air to travel through lines(20-30ft i've read) so it can cool first. 930

04-20-2009 12:47 PM

postal jeepster

Working on air brake systems over here in Afghanistan for the military I have come up with an idea I am going to try once I get back home. Trucks that use air brake systems have an "air drier" on the vehicle. Air gets routed thru the drier and a desicant material then to the storage tank. when the pressure gets to a set point, typically 125 psi, it "pops off" the supply pressure thru the air drier, removing the moisture that was collected. That is the big air blast that you might hear when a truck is running.
My idea is to mount this at my compressor and us it as the drier for my air system. Any thoughts? Aaron

01-25-2009 09:59 PM

930dreamer

I have eight industrial compressors the Quincy being the smallest. One 120 gallon tank will be a smoker/BBQ combo. Some of my tanks "look" very good on the inside but the unknown worries me. I guess I don't take the chances I once did. Thanks Shawn

01-25-2009 05:30 PM

oldred

Quote:

Originally Posted by 930dreamer

Not the most cost effective move.

I don't know if I would say that, it sounds like it may be a very cost effective move if the pump is in good shape. Those old pumps are are really tough and worth rebuilding if they are worn and if already in good shape they are definitly worth spending the cost of a new tank. My old Quincy pump is almost 40 years old and although I do have a certain sentimental attachment to it the thing still sees duty providing the air for my shop. I have it mounted remotely from the tank and removing the pump/motor vibration from the tank is a real plus for tank life if you have the room to spare. Sounds like a good plan to me!

01-25-2009 05:04 PM

930dreamer

Yes the tank looks bad, I've looked inside it and no I won't take a chance. I'll pair up the pump and motor on the platform and run the air to a new tank. Not the most cost effective move but will see. Thanks Shawn

01-25-2009 04:55 PM

DaSouthWon

Man, that tank looks a time bomb. I hope you get it checked before you try to use it. There is a whole thread on here about tank explosions. It's unlikely, but I would consider that tank to put you in the upper percentile of "those who have crazy stuff happen to them" rankings.

I think you may be missing what I am saying, the more vapor that enters the line the more water you have to deal with, water leaving the tank is considered water produced and water that remains in the tank is of little to no concern. So like Kgus said the hotter the compressor runs the more water it will produce, for practical purposes anyway, in the lines to be collected by the separator. If the air is properly cooled prior to the separator then that moisture will be removed and tank/air temperature will not matter but that is all too often the problem. When using a refrigerated dryer the temperature of the incoming air is usually of little concern unless the system is being overwhelmed by the volume of air flow but for most installations, especially the home type like most of the people here will be dealing with, the temperature of the air leaving the tank can be very important due to the fact it may not have the opportunity to cool properly before entering the separator. A lot of people here have experienced what I am (and Kgus) talking about, their system seems to be moisture free until the compressor is under a heavy demand and then water problems appear. This is due to insufficient cooling, for the most part, between the tank and separator and even when the system works properly more water is collected in the separator than when the compressor is under less load and running cooler, of course the difference will be contained in the tank.

BTW, like you I too have been selling and installing/servicing compressors and air systems since 1971 so I do understand what you are saying it is just that it seems we may be talking about two different things.

01-24-2009 12:59 PM

jaguarxk120

If you pass all the compressed air through a air drier then it matters not if you tank is hot or cold. The tank will stay "cold" only so long till the hot air from the compressor heats it up. If the water condense's and drops out in the tank so much the better, after that into a dryer and water trap, and you have dry air.
I've worked with large air systems for over thirty years and we always removed moisture before sending it out to the system, we had no tanks.

01-24-2009 11:51 AM

oldred

Quote:

Originally Posted by jaguarxk120

It does not matter as log as you get the temperture below the dew point and condense the vapor into water. Then have a good water trap at the discharge of the air drier. It is amazing how much water will condense during a very humid day. The trap will remove the condensate and you will have dry air.

True, that's the way it works but a tank full of heated air will pass more water vapor into the lines than a tank full of cold air. When the air is cooler in the tank more of the moisture will wind up being drained from the tank at the end of the day while overheated air from an overworked compressor will pass more of the water vapor out of the tank and into the air lines, the hotter the air the more vapor it will contain. In the end the total amount of water collected will theoretically remain the same it is just a matter of where it will end up, in the tank or in the water separator.

01-24-2009 11:38 AM

jaguarxk120

It does not matter as log as you get the temperture below the dew point and condense the vapor into water. Then have a good water trap at the discharge of the air drier. It is amazing how much water will condense during a very humid day. The trap will remove the condensate and you will have dry air.

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